The docking of a US nuclear- powered submarine in northern Philippine province of Zambales has diplomatic clearance, a senior government official said Friday.

Deputy presidential spokesperson Abigail Valte issued the statement amid opposition by some leftist groups to the scheduled arrival on Friday of USCheyenne in the former US naval base in Subic Bay.

"This (arrival of US submarine) has diplomatic clearance from the Department of Foreign Affairs and in consultation with the Department of National Defense and our navy for a routine replenishment," she told a news briefing.

USCheyenne's visit to the Philippines is under the auspices of the Visiting Forces Agreement between the two governments.

Valte also clarified that under the Constitution what is prohibited is the entry of nuclear armaments, not a nuclear- powered vessel.

The arrival of a US submarine came amid the grounding of USGuardian in Tubbataha Reef off Sulu Sea.

Valte said the government expects USCheyenne to take all the necessary precautions to avoid similar accident in the Unesco World Heritage site.